Our long-term goal is to elucidate the relationship between neural activity, sound processing, perception and behavior. We specifically propose to establish the relationship of neural activity to discriminating temporal and spectral sound features in the primary auditory cortex (A1) and anterior lateral belt area (AL) of non-human subjects. Previously, we have determined their ability to detect and discriminate temporal and spectral sound features. We now approach the question: How do neuronal responses in auditory cortical core and belt areas relate to non-human subjects' psychophysical and behavioral performance? The three aims are designed to compare three fundamental aspects related to these issues in a core and in a lateral belt area to determine the changing emphasis of processing along the ascending cortical pathway. Aim 1 is to determine the neural basis of spectral and temporal modulation detection. Aim 2 is to determine how single neuron responses from auditory cortex are related to perception and behavioral choices. Aim 3 is to determine the effect of behavioral state and task-engagement on neurons ability to encode temporal modulations. To achieve these aims, we will establish the quantitative relationships between single unit auditory cortical (AC) activity and the ability of neurons and non-human subjects to discriminate sounds, and determine what codes most likely underlie perceptual ability. We will also record from single units while non-human subjects discriminate sound to determine the role of primary and secondary sensory cortical areas in the transformation from sensation to task performance. This will give insight into how active engagement in a task improves neural processing ability at the single neuron level and whether primary sensory cortex receives information or is involved in the processes that lead to action. Because the proposal relates brain function to different parts of the brain it is relevant for a better understanding about how punctate brain damage such as that cause by stroke affects auditory function. The results of these studies will help us to better understand how attending sound modulates auditory activity and thus makes this basic science have relevance for the spectrum disorders (that include, but are not limited to attention deficit disorder, dyslexia, etc). The results also could have relevance in helping to guide approaches to coding for hearing aids and cochlear implants since both neural coding and the ability to focus on sounds are relevant for designing these devices.